package com.mapfinal.fileserver;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import com.lambkit.Lambkit;
import com.lambkit.common.util.ImageUtils;
import com.mapfinal.server.MapfinalServerConfig;

/**
 * 文件存储（托管、代理缓存）管理
 * @author yangyong
 *
 */
public class FileStorageManager {
	
	private static FileStorageManager manager;

	private FileStorageManager() {
	}

	public static FileStorageManager me() {
		if(manager==null) {
			manager = new FileStorageManager();
		}
		return manager;
	}
	
	public boolean hasFile(String materialFileName) {
		MapfinalServerConfig config = Lambkit.config(MapfinalServerConfig.class);
		File file = new File(config.getFileCachePath() + File.separator + materialFileName);
		return file.exists();
	}
	
	public String getFile(String materialFileName, String url, String type) throws IOException {
		boolean bextimage = ImageUtils.isImageExtName(materialFileName);
		MapfinalServerConfig config = Lambkit.config(MapfinalServerConfig.class);
		if("thumbnail".equals(type) && bextimage) {
			String thumbnailFile = config.getFileCachePath() + File.separator + "thumbnail" + File.separator + materialFileName;
			File file = new File(thumbnailFile);
			if(file.exists()) {
				return thumbnailFile;
			} else {
				downLoadFromUrl(url, materialFileName, config.getFileCachePath());
				String srcImageFile = config.getFileCachePath() + File.separator + materialFileName;
				ImageUtils.zoom(256, srcImageFile, thumbnailFile);
				return thumbnailFile;
			}
		} else {
			String srcImageFile = config.getFileCachePath() + File.separator + materialFileName;
			File file = new File(srcImageFile);
			if(file.exists()) {
				return srcImageFile;
			} else {
				downLoadFromUrl(url, materialFileName, config.getFileCachePath());
				String thumbnailFile = config.getFileCachePath() + File.separator + "thumbnail" + File.separator + materialFileName;
				if(bextimage) {
					ImageUtils.zoom(256, srcImageFile, thumbnailFile);
				}
				return srcImageFile;
			}
		}
		
	}
	
	/**
	 * 从网络Url中下载文件
	 * 
	 * @param urlStr
	 * @param fileName
	 * @param savePath
	 * @throws IOException
	 */
	private void downLoadFromUrl(String urlStr, String fileName, String savePath) throws IOException {
		URL url = new URL(urlStr);
		HttpURLConnection conn = (HttpURLConnection) url.openConnection();
		// 设置超时间为3秒
		conn.setConnectTimeout(3 * 1000);
		// 防止屏蔽程序抓取而返回403错误
		conn.setRequestProperty("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");

		// 得到输入流
		InputStream inputStream = conn.getInputStream();
		// 获取自己数组
		byte[] getData = readInputStream(inputStream);

		// 文件保存位置
		File saveDir = new File(savePath);
		if (!saveDir.exists()) {
			saveDir.mkdir();
		}
		File file = new File(saveDir + File.separator + fileName);
		FileOutputStream fos = new FileOutputStream(file);
		fos.write(getData);
		if (fos != null) {
			fos.close();
		}
		if (inputStream != null) {
			inputStream.close();
		}

		System.out.println("info:" + url + " download success");

	}
	
	/**
	 * 从输入流中获取字节数组
	 * 
	 * @param inputStream
	 * @return
	 * @throws IOException
	 */
	private byte[] readInputStream(InputStream inputStream) throws IOException {
		byte[] buffer = new byte[1024];
		int len = 0;
		ByteArrayOutputStream bos = new ByteArrayOutputStream();
		while ((len = inputStream.read(buffer)) != -1) {
			bos.write(buffer, 0, len);
		}
		bos.close();
		return bos.toByteArray();
	}
}
